Add remote info to the HLRC

client/rest-high-level/src/main/java/org/elasticsearch/client/ClusterClient.java

@@ -26,6 +26,8 @@
 import org.elasticsearch.action.admin.cluster.settings.ClusterGetSettingsResponse;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.elasticsearch.client.cluster.RemoteInfoRequest;
+import org.elasticsearch.client.cluster.RemoteInfoResponse;
 import org.elasticsearch.rest.RestStatus;
 
 import java.io.IOException;
@@ -138,4 +140,33 @@ public Cancellable healthAsync(ClusterHealthRequest healthRequest, RequestOption
         return restHighLevelClient.performRequestAsyncAndParseEntity(healthRequest, ClusterRequestConverters::clusterHealth, options,
                 ClusterHealthResponse::fromXContent, listener, singleton(RestStatus.REQUEST_TIMEOUT.getStatus()));
     }
+
+    /**
+     * Get the remote cluster information using the Remote cluster info API.
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-remote-info.html"> Remote cluster info
+     * API on elastic.co</a>
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public RemoteInfoResponse remoteInfo(RemoteInfoRequest request, RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity(request, ClusterRequestConverters::remoteInfo, options,
+                RemoteInfoResponse::fromXContent, singleton(RestStatus.REQUEST_TIMEOUT.getStatus()));
+    }
+
+    /**
+     * Asynchronously get remote cluster information using the Remote cluster info API.
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-remote-info.html"> Remote cluster info
+     * API on elastic.co</a>
+     * @param request the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return cancellable that may be used to cancel the request
+     */
+    public Cancellable remoteInfoAsync(RemoteInfoRequest request, RequestOptions options,
+                                       ActionListener<RemoteInfoResponse> listener) {
+        return restHighLevelClient.performRequestAsyncAndParseEntity(request, ClusterRequestConverters::remoteInfo, options,
+                RemoteInfoResponse::fromXContent, listener, singleton(RestStatus.REQUEST_TIMEOUT.getStatus()));
+    }
 }

client/rest-high-level/src/main/java/org/elasticsearch/client/ClusterRequestConverters.java

@@ -25,6 +25,7 @@
 import org.elasticsearch.action.admin.cluster.settings.ClusterGetSettingsRequest;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.elasticsearch.action.support.ActiveShardCount;
+import org.elasticsearch.client.cluster.RemoteInfoRequest;
 import org.elasticsearch.common.Strings;
 
 import java.io.IOException;
@@ -76,4 +77,8 @@ static Request clusterHealth(ClusterHealthRequest healthRequest) {
         request.addParameters(params.asMap());
         return request;
     }
+
+    static Request remoteInfo(RemoteInfoRequest remoteInfoRequest) {
+        return new Request(HttpGet.METHOD_NAME, "/_remote/info");
+    }
 }

client/rest-high-level/src/main/java/org/elasticsearch/client/cluster/ProxyModeInfo.java

@@ -0,0 +1,75 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.client.cluster;
+
+import java.util.Objects;
+
+public class ProxyModeInfo implements RemoteConnectionInfo.ModeInfo {
+    static final String NAME = "proxy";
+    static final String ADDRESS = "address";
+    static final String NUM_SOCKETS_CONNECTED = "num_sockets_connected";
+    static final String MAX_SOCKET_CONNECTIONS = "max_socket_connections";
+    private final String address;
+    private final int maxSocketConnections;
+    private final int numSocketsConnected;
+
+    ProxyModeInfo(String address, int maxSocketConnections, int numSocketsConnected) {
+        this.address = address;
+        this.maxSocketConnections = maxSocketConnections;
+        this.numSocketsConnected = numSocketsConnected;
+    }
+
+    @Override
+    public boolean isConnected() {
+        return numSocketsConnected > 0;
+    }
+
+    @Override
+    public String modeName() {
+        return NAME;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public int getMaxSocketConnections() {
+        return maxSocketConnections;
+    }
+
+    public int getNumSocketsConnected() {
+        return numSocketsConnected;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ProxyModeInfo otherProxy = (ProxyModeInfo) o;
+        return maxSocketConnections == otherProxy.maxSocketConnections &&
+                numSocketsConnected == otherProxy.numSocketsConnected &&
+                Objects.equals(address, otherProxy.address);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(address, maxSocketConnections, numSocketsConnected);
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/cluster/RemoteConnectionInfo.java

@@ -0,0 +1,137 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.client.cluster;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.ConstructingObjectParser;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+
+/**
+ * This class encapsulates all remote cluster information to be rendered on
+ * {@code _remote/info} requests.
+ */
+public final class RemoteConnectionInfo {
+    private static final String CONNECTED = "connected";
+    private static final String MODE = "mode";
+    private static final String INITIAL_CONNECT_TIMEOUT = "initial_connect_timeout";
+    private static final String SKIP_UNAVAILABLE = "skip_unavailable";
+
+    @SuppressWarnings("unchecked")
+    private static final ConstructingObjectParser<RemoteConnectionInfo, String> PARSER = new ConstructingObjectParser<>(
+            "RemoteConnectionInfoObjectParser",
+            false,
+            (args, clusterAlias) -> {
+                String mode = (String) args[1];
+                ModeInfo modeInfo;
+                if (mode.equals(ProxyModeInfo.NAME)) {
+                    modeInfo = new ProxyModeInfo((String) args[4], (int) args[5], (int) args[6]);
+                } else if (mode.equals(SniffModeInfo.NAME)) {
+                    modeInfo = new SniffModeInfo((List<String>) args[7], (int) args[8], (int) args[9]);
+                } else {
+                    throw new IllegalArgumentException("mode cannot be " + mode);
+                }
+                return new RemoteConnectionInfo(clusterAlias,
+                        modeInfo,
+                        TimeValue.parseTimeValue((String) args[2], INITIAL_CONNECT_TIMEOUT),
+                        (boolean) args[3]);
+            });
+
+    static {
+        PARSER.declareBoolean(constructorArg(), new ParseField(CONNECTED));
+        PARSER.declareString(constructorArg(), new ParseField(MODE));
+        PARSER.declareString(constructorArg(), new ParseField(INITIAL_CONNECT_TIMEOUT));
+        PARSER.declareBoolean(constructorArg(), new ParseField(SKIP_UNAVAILABLE));
+
+        PARSER.declareString(optionalConstructorArg(), new ParseField(ProxyModeInfo.ADDRESS));
+        PARSER.declareInt(optionalConstructorArg(), new ParseField(ProxyModeInfo.MAX_SOCKET_CONNECTIONS));
+        PARSER.declareInt(optionalConstructorArg(), new ParseField(ProxyModeInfo.NUM_SOCKETS_CONNECTED));
+
+        PARSER.declareStringArray(optionalConstructorArg(), new ParseField(SniffModeInfo.SEEDS));
+        PARSER.declareInt(optionalConstructorArg(), new ParseField(SniffModeInfo.MAX_CONNECTIONS_PER_CLUSTER));
+        PARSER.declareInt(optionalConstructorArg(), new ParseField(SniffModeInfo.NUM_NODES_CONNECTED));
+    }
+
+    final ModeInfo modeInfo;
+    final TimeValue initialConnectionTimeout;
+    final String clusterAlias;
+    final boolean skipUnavailable;
+
+    RemoteConnectionInfo(String clusterAlias, ModeInfo modeInfo, TimeValue initialConnectionTimeout, boolean skipUnavailable) {
+        this.clusterAlias = clusterAlias;
+        this.modeInfo = modeInfo;
+        this.initialConnectionTimeout = initialConnectionTimeout;
+        this.skipUnavailable = skipUnavailable;
+    }
+
+    public boolean isConnected() {
+        return modeInfo.isConnected();
+    }
+
+    public String getClusterAlias() {
+        return clusterAlias;
+    }
+
+    public ModeInfo getModeInfo() {
+        return modeInfo;
+    }
+
+    public TimeValue getInitialConnectionTimeout() {
+        return initialConnectionTimeout;
+    }
+
+    public boolean isSkipUnavailable() {
+        return skipUnavailable;
+    }
+
+    public static RemoteConnectionInfo fromXContent(XContentParser parser, String clusterAlias) throws IOException {
+        return PARSER.parse(parser, clusterAlias);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        RemoteConnectionInfo that = (RemoteConnectionInfo) o;
+        return skipUnavailable == that.skipUnavailable &&
+                Objects.equals(modeInfo, that.modeInfo) &&
+                Objects.equals(initialConnectionTimeout, that.initialConnectionTimeout) &&
+                Objects.equals(clusterAlias, that.clusterAlias);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(modeInfo, initialConnectionTimeout, clusterAlias, skipUnavailable);
+    }
+
+    public interface ModeInfo {
+
+        boolean isConnected();
+
+        String modeName();
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/cluster/RemoteInfoRequest.java

@@ -0,0 +1,28 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.cluster;
+
+import org.elasticsearch.client.Validatable;
+
+/**
+ * The request object used by the Remote cluster info API.
+ */
+public final class RemoteInfoRequest implements Validatable {
+
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/cluster/RemoteInfoResponse.java

@@ -0,0 +1,59 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.cluster;
+
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import static org.elasticsearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+
+/**
+ * A response to _remote/info API request.
+ */
+public final class RemoteInfoResponse {
+
+    private List<RemoteConnectionInfo> infos;
+
+    RemoteInfoResponse(Collection<RemoteConnectionInfo> infos) {
+        this.infos = List.copyOf(infos);
+    }
+
+    public List<RemoteConnectionInfo> getInfos() {
+        return infos;
+    }
+
+    public static RemoteInfoResponse fromXContent(XContentParser parser) throws IOException {
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser::getTokenLocation);
+
+        List<RemoteConnectionInfo> infos = new ArrayList<>();
+
+        XContentParser.Token token;
+        while ((token = parser.nextToken()) == XContentParser.Token.FIELD_NAME) {
+            String clusterAlias = parser.currentName();
+            RemoteConnectionInfo info = RemoteConnectionInfo.fromXContent(parser, clusterAlias);
+            infos.add(info);
+        }
+        ensureExpectedToken(XContentParser.Token.END_OBJECT, token, parser::getTokenLocation);
+        return new RemoteInfoResponse(infos);
+    }
+}